J Psychiatry Neurosci 2014; 39(3): 170-177
Zhiyun Jia, MD, PhD; Yuqing Wang, PhD; Xiaoqi Huang, PhD; Weihong Kuang, MD; Qizhu Wu, PhD; Su Lui, MD, PhD; John A. Sweeney, PhD; Qiyong Gong, MD, PhD
Jia, Wang, Huang, Wu, Lui, Gong — Huaxi Magnetic Resonance Research Center (HMRRC), Department of Radiology, West China Hospital of Sichuan University, Chengdu, China; Kuang — Department of Psychiatry, State Key Lab of Biotherapy, West China Hospital of Sichuan University, Chengdu, China; Sweeney — Departments of Psychiatry and Pediatrics, University of Texas Southwestern, Dallas, Tex., USA
Background: The neurobiology of suicide is largely unknown. Studies of white matter tracts in patients with a history of suicidal behaviour have shown alteration in the left anterior limb of the internal capsule (ALIC). Our aim was to determine whether particular target fields of fibre projections through the ALIC are affected in depressed patients who recently attempted suicide.
Methods: We studied patients with major depressive disorder (MDD) with and without a history of suicide attempts and healthy controls using diffusion tensor imaging (DTI) and deterministic tractography to generate fibre tract maps for each participant. Tract voxels were coded as being unique to the left ALIC. We compared the mean percentage of fibres projecting to relevant brain regions in the 3 groups using analysis of covariance.
Results: We included 63 patients with MDD (23 with and 40 without a history of suicide attempts) and 46 controls in our study. Both groups of depressed patients had reduced fibre projections through the ALIC to the left medial frontal cortex, orbitofrontal cortex and thalamus. Those with a history of suicide attempts had greater abnormalities than those without suicide attempts in the left orbitofrontal cortex and thalamus.
Limitations: Diffusion tensor imaging deterministic tracking is unable to distinguish between afferent and efferent pathways, limiting our ability to distinguish the directionality of altered fibre tracts.
Conclusions: Frontothalamic loops passing through the ALIC are abnormal in patients with depression and significantly more abnormal in depressed patients with a history of suicide attempts than in those without a history of suicide attempts. Abnormal projections to the orbitofrontal cortex and thalamus may
disrupt affective and cognitive functions to confer a heightened vulnerability for suicidal behaviour.
Submitted Feb. 7, 2013; Revised May 27, July 10, 2013; Accepted July 15, 2013.
Acknowledgements: This study was supported by National Natural Science Foundation (Grant Nos. 81030027, 81271532, 30900378, 81227002 and 81220108013), National Key Technologies R&D Program of China (Program No: 12BAI01B03) and the Program for Changjiang Scholars and Innovative Research Team in University (PCSIRT) of China. The authors want to acknowledge the American CMB Distinguished Professorship Award to Q. Gong and a Von Humboldt Research Award to J.A. Sweeney. Q. Gong also acknow ledges his Visiting Adjunct Professor appointment in the Department of Radiology at the University of Illinois Hospital & Health Sciences System, Chicago (IL), USA.
Competing interests: J. Sweeney has received support from BMS, Roche, Lilly, Takeda and Janssen.
Contributors: Z. Jia and Q. Gong designed the study. X. Huang, W. Kuang, Q. Wu and S. Lui acquired the data, which Z. Jia, Y. Wang, W. Kuang, J.A. Sweeney and Q. Gong analyzed. Z. Jia, Y.Wang, J.A. Sweeney and Q. Gong wrote the article, which all authors reviewed and approved for publication.
Correspondence to: Q. Gong, Huaxi Magnetic Resonance Research Center (HMRRC), Department of Radiology, West China Hospital of Sichuan University, Chengdu 610041, China; firstname.lastname@example.org